The invention concerns a hoisting device with a drive unit consisting of a motor and a transmission, a drive shaft which can be driven by the drive unit, with a drive flange which can be secured to it, and a cable drum which can be connected to the drive flange, wherein the torque of the drive shaft can be transmitted to the cable drum across a coupling.
Hoisting devices configured as a cable string basically comprise cylindrical cable drums, which are mounted so as to turn in a frame. The cable drum is driven by means of a gear motor, the output shaft of the transmission being coupled torsion-free to the cable drum. In order to equalize the manufacturing tolerances and alignment errors of the cable drum, which is generally outfitted with a so-called “three-point bearing”, such as might lead to strains in the drive system, it is known from practice how to arrange a coupling between the output shaft and the cable drum in a manner that can take up these alignment errors.
In the so-called Zapex coupling, the coupling is fashioned as a toothed coupling, which comprises a pinion joined torsion-free to the output shaft and a toothed rim meshing with this pinion and secured to the drive flange of the cable drum.
Furthermore, the so-called TGL coupling is known, in which a flange secured torsion-free to the output shaft engages by one or more driving lugs with recesses in an end wall of the cable drum.
Both coupling mechanisms have become quite common in practice, although they have the drawback that they are relatively costly for mass-produced lifting mechanisms with relatively low drum torque and furthermore they cannot be used with small drum diameters, for space considerations owing to their size.
DE 298 16 675 U1 discloses a coupling for lifting mechanisms for transmitting the torque of a driven transmission shaft to a cable drum, with a coupling hub arranged at one end of the transmission shaft and with a coupling housing arranged on the coupling hub and enclosed by inner and outer covers. The coupling housing and the coupling hub are form-fitted together by circular gearings formed on the coupling housing and the coupling hub, and in the bores formed by the two circular gearings there are arranged barrel rollers to transmit the force.